Master cylinder cap



y 1967 w. E. FERRELL ETAL 3,317,079

MASTER CYLINDER CAP Filed March 29, 1965 U INVI ZNTORS I; E WMAJAM E. FERRELL.

HEQAZAN M.HUFFMAN. Y

ATTORNEY.

United States Patent 3,317,079 MASTER CYLINDER CAP William E. Ferrell, St. Joseph, and Herman M. Hulfman,

Kalamazoo, Mich., assignors to The Bendix Corporation, St. Joseph, Mich., a corporation of Delaware Filed Mar. 29, 1965, Ser. No. 443,535 7 Claims. (Cl. 220-40) This invention relates to a cap for a master cylinder.

An object of this invention is to provide a master cylinder reservoir with a cap which may be readily manufactured, economical and yet efficient.

Other objects of the invention will become apparent from the following description with reference to the drawings wherein:

FIGURE 1 is a front view of a master cylinder reservoir and cap;

FIGURE 2 is a plan view of FIGURE 1;

FIGURE 3 is an enlarged end view of a bayonet connection between the cap and the reservoir; and

FIGURE 4 is an enlarged side view of a portion of the cap.

Referring to the drawings, there is illustrated a standard master cylinder casting with a plastic reservoir 12 secured thereto by any known manner. A cap is releasably secured to the reservoir and comprises a generally cupshaped plastic top 14 and a flexible rubber diaphragm 16 bridging the cavity 17 formed by the top member 14. A plurality of flanges 18 extend outwardly from a cylindrical wall 20 of the top member and are located between the axially spaced ends of the wall 20. The rubber diaphragm 16 comprises a central disc portion 22, a convolute 24, and a reverse convolute 26 terminating in an annular peripheral bead 28. The open end of the cylindrical wall 20 is received within the reverse convolute 26 and has an annular groove receiving the bead 28 therein which secures the diaphragm 16 to the top member 14. A plurality of annular sealing ribs 29 project from the bead 28 and are constructed to project beyond the outer surface of the wall 20 prior to fastening the cap to the reservoir 12 so that the bead 28 will be compressed between the reservoir wall 34 and the wall 20 of the top member to effect a seal therebetween when the cap is secured to the reservoir. A vent 32 is provided in the wall 20 of the top member for venting the cavity 17.

The reservoir 12 comprises an annular wall 34 having three circumferentially spaced lugs 36 extending upward from the end thereof. An opening 38 is provided in each flange 18 for receiving a respective one of the lugs 36 therethrou gh. Each lug has a radial finger 40 and each opening 38 comprises two sections 42 and 44 with the section 42 being radially wider than the section 44 to receive the finger 40 therethrough. The radial width of the finger 40 is greater than the radial width of the section 44. A rib 46 projects from the flange 18 and is located between the sections 42 and 44 of the opening 38. One end of the bottom edge of the finger 40 is beveled at 48 providing a camming edge on which the rib is cammed past the lug 40. The other end of the bottom edge of finger 40 is very slightly beveled at 50 to provide a locking abutment between the finger 40 and the rib 46 but yet permit riding of the rib 46 under the corner 50 when considerable rotational force is applied to the cap. The distance between the top edge of the wall 34 and the bottom edge of finger 40 is slightly greater than the thickness of flange 18 so that the rib 46 may be cammed past finger 40.

To fasten the cap to the reservoir, one places the cap over the reservoir; aligns the lugs 36 with their respective opening sections 42; lowers the cap into the reservoir until the flange 20 engages the end of the Wall 34, and with the lugs 36 extending through their respective sections 42; then twists the cap in a clockwise direction whereby the 3,317,079 Patented May 2, 1967 rib 46 will ride under the finger 40 until rib 46 snaps past the corner 50 of the finger 40. Since the finger 40 is radially wider than the radial width of the section 44, the finger prevents upward axial movement of the cap, and the cap is now locked on the reservoir. The cap may be removed by twisting in a counterclockwise direction, but due to the fact that the edge 50 is only slightly beveled, much more force will be required to twist the cap counterclockwise to release the same than clockwise to secure the same to the reservoir.

The interior of the reservoir is completely sealed from any contaminates entering through vent 32 by the diaphragm 16 and from any contaminates entering between the cap and reservoir by the head 28.

From the above, it can be seen that a simple two-piece cap has been produced and yet the sealing qualities required of a cap are present in this cap.

Although this invention has been described in considerable detail, we do not wish to be limited thereby and intend to cover all equivalent constructions within the scope of the following claims:

What is claimed is:

1. The combination of a master cylinder reservoir and cap comprising: a cap and a hollow reservoir member, said cap comprising an annular wall closed at the top end by a portion transverse thereto thereby defining a cavity, flange means intermediate the ends of said annular wall, the outer surface of said wall having an annular relieved portion extending between said flange means and the open end of said wall, a flexible sealing member bridging the entire cavity and having its outer peripheral portion received in said relieved portion, vent means in said cap for venting said cavity, said reservoir member having an upper open end annular wall portion receiving the lower end of said annular Wall of said cap therein, said peripheral portion of said sealing member compressively engaging the inner surface of said reservoir Wall, the bottom surface of said flange means engaging the end of said reservoir wall at the open end thereof, at least one lug extending upwards from the open end of said reservoir wall, said lug including a finger extending radially outwards therefrom, at least one opening in said flange means, said finger extending through said opening in said flange means, said opening having an initial finger receiving section of radial width at least equal to the radial length of said finger and a finger retaining section of radial width smaller than the radial length of said finger, said finger and sections being so located that upon rotation of said cap in one direction said finger will be located within said finger retainer section of said opening, whereby said cap is removably secured to said reservoir member.

2. The structure as recited in claim 1 wherein said sealing member is carried by said cap.

3. The structure as recited in claim 1 wherein said relieved portion comprises an annular groove, said outer peripheral portion of said sealing member comprises an annular bead located within said groove whereby said sealing member is carried by said cap.

4. The structure as recited in claim 3 wherein said transverse portion of said cap, said annular wall of said cap, said flange means of said cap are integral and said lug is integral with said reservoir member.

5. The structure as recited in claim 3 wherein a plurality of spaced annular ribs extend from said annular bead and engage said inner surface of said reservoir wall.

6. The structure as recited in claim 4 wherein a rib is located on the upper surface of said flange and between said finger receiving section and said finger retaining section of said opening, the bottom edge of said finger comprises portions which are beveled from each lateral end thereof in a direction toward the center, one of said finger edge portions is beveled at an angle with respect to the plane of said flange which is substantially greater than the bevel angle of the other of said finger edge portions, said finger is arranged relative to said rib so that said other finger edge portion is engaged by said rib for camming said rib past said finger when said cap is rotated in said one direction and said one finger edge is engaged by said rib for camming said rib past said finger when said cap is rotated in the opposite direction whereby rotation of said cap to secure it to said reservoir requires substantially less force than rotation of said cap to remove it from said reservoir.

7. The combination of a master cylinder reservoir and cap comprising: a cap and a hollow reservoir member, said cap comprising an annular wall closed at the top end by a portion transverse thereto thereby defining a cavity, flange means intermediate the ends thereof, said reservoir member having an upper open end annular wall portion receiving the lower end of said annular wall of said cap thereon, the bottom surface of said flange means engaging the end of said reservoir wall at the open end thereof, at

least one lug extending upwards from the open end of said reservoir Wall, said lug including a finger extending radially outward therefrom, at least one opening in said flange means, said finger extending into said opening in said flange means, said opening having an initial finger receiving section of radial width at least equal to the radial length of said finger and a finger retaining section of radial width smaller than the radial length of said finger, said finger and sections being so located that upon rotation of said cap in one direction said finger will be located within said lug retaining section of said opening to thereby secure said cap to said reservoir member, a rib located on the upper surface of said flange and between said finger receiving section and said finger retaining section of said opening, the bottom edge of said finger comprising portions which are beveled from each lateral end thereof in a direction toward the center, one of said finger edge portions being beveled at an angle with respect to the plane of said flange which is substantially greater than the bevel angle of the other of said finger edge portions, said finger being arranged relative to said rib so that said other finger edge portion is engaged by said rib for camming said rib past said finger when said cap is rotated in said one direction and said one finger edge is engaged by said rib for camming said rib past said finger when said cap is rotated in the opposite direction whereby rotation of said cap to secure it to said reservoir requires substantially less force than rotation of said cap to remove it from said reservoir.

No references cited.

THERON E. CONDON, Primary Examiner. I. B. MARBERT, Assistant Examiner. 

1. THE COMBINATION OF A MASTER CYLINDER RESERVOIR AND CAP COMPRISING: A CAP AND A HOLLOW RESERVOIR MEMBER, SAID CAP COMPRISING AN ANNULAR WALL CLOSED AT THE TOP END BY A PORTION TRANSVERSE THERETO THEREBY DEFINING A CAVITY, FLANGE MEANS INTERMEDIATE THE ENDS OF SAID ANNULAR WALL, THE OUTER SURFACE OF SAID WALL HAVING AN ANNULAR RELIEVED PORTION EXTENDING BETWEEN SAID FLANGE MEANS AND THE OPEN END OF SAID WALL, A FLEXIBLE SEALING MEMBER BRIDGING THE ENTIRE CAVITY AND HAVING ITS OUTER PERIPHERAL PORTION RECEIVED IN SAID RELIEVED PORTION, VENT MEANS IN SAID CAP FOR VENTING SAID CAVITY, SAID RESERVOIR MEMBER HAVING AN UPPER OPEN END ANNULAR WALL PORTION RECEIVING THE LOWER END OF SAID ANNULAR WALL OF SAID RESERVOIR RECEIVING THE LOWER END PORTION OF SAID SEALING MEMBER COMPRESSIVELY ENGAGING THE INNER SURFACE OF SAID RESERVOIR WALL, THE BOTTOM SURFACE OF SAID FLANGE MEANS ENGAGING THE END OF SAID RESERVOIR WALL AT THE OPEN END THEREOF, AT LEAST ONE LUG EXTENDING UPWARDS FROM THE OPEN END OF SAID RESERVOIR WALL, SAID LUG INCLUDING A FINGER EXTENDING RADIALLY OUTWARDS THEREFROM, AT LEAST ONE OPENING IN SAID FLANGE MEANS, SAID FINGER EXTENDING THROUGH SAID OPENING IN SAID FLANGE MEANS, SAID OPENING HAVING AN INITIAL FINGER RECEIVING SECTION OF RADIAL WIDTH AT LEAST EQUAL TO THE RADIAL LENGTH OF SAID FINGER AND A FINGER RETAINING SECTION OF RADIAL WIDTH SMALLER THAN THE RADIAL LENGTH OF SAID FINGER, SAID FINGER AND SECTIONS BEING SO LOCATED THAT UPON ROTATION OF SAID CAP IN ONE DIRECTION SAID FINGER WILL BE LOCATED WITHIN SAID FINGER RETAINER SECTION OF SAID OPENING, WHEREBY SAID CAP IS REMOVABLY SECURED TO SAID RESERVOIR MEMBER. 